enhances-lme4.R
In visreg: Visualization of Regression Models

library(lme4)

# Make up some data
n <- 10
j <- 3
alpha <- rnorm(n)
ID <- rep(1:n, j)
x <- runif(n * j)
y <- rnorm(n * j, mean = x + alpha[ID], sd = 0.5)
df <- data.frame(y = y, x = x, ID = factor(ID))

fit <- lmer(y ~ x + (1 | ID), data = df)
visreg(fit, "x")
visreg(fit, "x", by = "ID")
visreg(fit, "x", by = "ID", re.form = ~ (1 | ID)) # Adds random effects back in

visreg(fit, "x", by = "ID", overlay = TRUE, strip.names = TRUE)
v <- visreg(fit, "x", by = "ID", re.form = ~ 1 | ID)
plot(v, overlay = TRUE, strip.names = FALSE)
plot(v, overlay = TRUE, strip.names = TRUE)
plot(v, overlay = TRUE, strip.names = LETTERS[1:10])

visreg(fit, "x", type = "contrast")
visreg(fit, "x", by = "ID", type = "contrast")

# Works with a cbind() formula
y1 <- sample(101:200, n * j, replace = TRUE)
y2 <- sample(0:100, n * j, replace = TRUE)
df <- data.frame(y1 = y1, y2 = y2, x = x, ID = factor(ID))

fit <- glmer(cbind(y1, y2) ~ x + (1 | ID), data = df, family = "binomial")
visreg(fit, "x")